1. Field of the Invention
The present invention relates to a quantitative determination method of chemicals for processing semiconductor, and more particularly, to quantitative analysis of the chemicals by near-infrared spectrometry at 800-1400 nm and an apparatus therefor.
2. Prior art
In a field of semiconductors it is a problem to be solved to determine the concentration of an aqueous solution of the chemicals for processing a semiconductor by an accurate, easy and rapid method.
With respect to treating chemicals such as acids (sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid and the like), alkaline solutions (aqueous solution of ammonium and the like), solution of redox material (aqueous solution of hydrogen peroxide and the like) and the like which are used in a washing process of silicon wafer, photoetching process and the like, automation of chemical analysis and supply of the treating chemicals is required from the viewpoints of yield increase of product, safety, working efficiency and the like.
Heretofore, titration method, electrolysis method at constant potential and analytical method using electrodes such as redox electrodes, electrodes for selecting ions and the like are employed for this purpose.
However, the concentration cannot be determined in a short time by the titration method; stable measurement cannot be carried out for a long time by the electrolysis method because surfaces of electrodes are contaminated and the temperature of the sample to be determined is changed during measurement; therefore it is necessary for the method not only to adjust the concentration and pH of the sample to suitable ranges but also to add a standard into the sample.